This invention relates to a fuel injection system for an engine and more particularly to an improved type of fuel injection system that is particularly adapted for use in a two cycle or ported engine.
As noted in the co-pending application aforenoted, fuel injection systems for internal combustion engines have generally fallen into two types. These two types are the direct cylinder injected type or the manifold type. In addition, some fuel injectors in addition to injecting fuel also inject a gas under pressure such as air. The previously proposed injection systems of these general types have had a number of disadvantages which are detailed in the aforenoted co-pending application. As is disclosed in that application, there are a number of embodiments which enjoy the advantages of direct cylinder fuel injection without having the disadvantages of such direct cylinder injectors. In addition, the systems disclosed in that application permit the injection of fuel and air under pressure without having the disadvantages of the prior art type of fuel/air injection systems.
It is a principal object to this invention to provide further advantages in fuel injection systems of the type as described in the aforenoted co-pending application.
In the co-pending application, a chamber is formed that communicates with the combustion chamber under some phases of the engine operation through a nozzle port formed in the cylinder itself. Fuel is sprayed into this chamber and is delivered to the combustion chamber through the nozzle port under the influence of a high pressure air flow. Although that construction and those embodiments shown in the earlier application have a number of advantages, still further advantages can be enjoyed.
Specifically, it is desirable to insure that all of the fuel sprayed into the chamber is discharged during each cycle when the injection port is opened. Any fuel that may remain in the chamber after the injection port is closed will enter the combustion chamber on the next opening of the injection port and this fuel can be swept out of the exhaust port causing poor fuel economy and also high hydrocarbon emissions.
It is, therefore, a principal object to this invention to provide an fuel injection system of that general type wherein it is insured that all of the fuel will be discharged from the chamber into which it is injected each time the nozzle port is opened and closed so that no residual fuel will remain in the chamber from cycle to cycle.
When fuel is injected into a small chamber for later injection into the combustion chamber through an injection port, there is a danger of fuel condensation in the chamber or in the nozzle port or the area around the nozzle port when it is opened.
It is, therefore, a still further object to this invention to provide an improved arrangement for insuring a good vaporization of the fuel that is delivered from the chamber through the injection port.